The present invention relates to an electronic gas-lighting device having electromagnetic-noise suppressing means and which can be fitted extremely quickly and efficiently to a metal conducting body element of an electric household appliance, in particular a cooking range of a gas cooker.
Cooking ranges are known featuring integrated electric/electronic gas-lighters which are operated manually by means of pushbuttons to generate a spark by which to light one of the gas burners on the range. Known gas-lighters comprise a current-discharge generating circuit connected to one or more output terminals, each of which is connected by a conducting wire to an electrode located close to a burner to be lit: the electrodes are grounded by the range to which they are fitted. A spark is therefore generated between each electrode and each burner whenever a current discharge is generated in the circuit.
The current-discharge generating circuit may be conformed differently, but normally always poses the problem of also generating, during discharge, electromagnetic noise which may interfere with more delicate electronic equipment, such as radios, televisions, etc. For this reason, international standards provide for fitting the discharge generating circuitxe2x80x94or, more generally speaking, the gas-lighting devicexe2x80x94with noise suppressing means which normally comprise an electronic filter fitted upstream from the generating circuit, towards the electricity mains. Most known noise suppressing means need grounding and, in known lighting devices, the ground connectionxe2x80x94which is only called upon to withstand low currents (less than 1 and usually of about 0.1 ampere)xe2x80x94is made by means of a wire fitted to a terminal board supplying the range, or to a contact in turn fitted to the range, which is grounded by the terminal board. The wire must be connected to the noise suppressing means, which is done using removable connectors, such as Faston contacts, or by soldering. Whichever the case, grounding the noise suppressing means involves considerable cost, greatly increases the time taken to assemble the range, and prevents the range from being assembled automatically. What is more, the terminals to which the high-voltage current discharges are sent may interact with the metal of which the range is made and generate parasitic discharges which are dispersed to ground, thus impairing operation of the gas-lighting device.
It is an object of the present invention to provide an electronic gas-lighting device designed to eliminate the aforementioned drawbacks, and which, is particular, provides for straightforward, fast, low-cost grounding of the noise suppressing means by means of straightforward movements permitting automatic assembly of the gas-lighting device as a whole.
According to the present invention, there is provided an electronic gas-lighting device comprising a casing made of insulating material and defined by a cup-shaped body; electronic high-voltage-pulse generating means and electromagnetic-noise suppressing means, both housed in an inner cavity of the casing; a ground connection for said noise suppressing means; and assembly means for removably fitting said casing to a supporting surface of a metal conducting body element of an electric household appliance, in particular, a cooking range with gas burners for which said gas-lighting device is designed; characterized in that the ground connection is defined by an elastically deformable conducting element which is connected electrically to said noise suppressing means, projects outside said cavity on the same side as said assembly means, is positioned facing at least part of an outer surface of the casing, and is so formed as to be interposed, in use, between the casing and said metal conducting body element and gripped between the casing and the metal conducting body element by means of said assembly means.
More specifically, said conducting element defining the ground connection of the noise suppressing means is defined by a substantially U-shaped contact bracket fitted astride an edgexe2x80x94defining a mouth of said cavityxe2x80x94of the cup-shaped body defining the casing; the bracket comprising a first branch located inside the casing and connected electrically and mechanically to the noise suppressing means, and a second branch which is located outside the casing, is positioned facing and at a distance from said outer surface of the casing, and is elastically deformable to vary the distance between itself and said outer surface of the casing.
When fitting the device to the cooking range, which is conductive, the only connection required, therefore, is a normal removable mechanical connection of the nonconducting body of the gas-lighting device to the cooking range by means of said assembly means. In so doing, in fact, the U-shaped contact bracket is gripped between the casing and the range, and the outer branch of the bracket is deformed elastically, is xe2x80x9cpinchedxe2x80x9d between the range and the outer surface of the casing, and so mechanically and electrically contacts, with a predetermined pressure, the conducting surface of the range to effect the desired ground connection.
The assembly means may be of any type, for example, screws inserted through seats in the casing, or, according to a preferred embodiment, two teethxe2x80x94at least one of which is elastically deformablexe2x80x94formed in one piece with and projecting laterally from said casing, on the same side as the U-shaped contact bracket, and in particular in a direction substantially perpendicular to a lateral face of the casing having said edge astride which said U-shaped contact bracket is fitted.
Said lateral face of the casing is also provided externally with at least two pins or projections projecting with respect to said outer surface of the casing and for keeping the outer surface of the casing detached, in use, from the conducting surface of the cooking range and so increasing the distance, in use, between the conducting surface and at least one respective terminalxe2x80x94of a circuit defining said electronic pulse generating meansxe2x80x94housed through a duct defined by a tubular projection which is formed integrally with the casing and projects perpendicularly from a bottom wall, substantially perpendicular to said lateral face with the pins or projections, of the cup-shaped body defining the casing.
Said U-shaped contact bracket is preferably positioned with the second branch astride one said pin or projection.